Sail Trim And Balance Fundamental


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Sail Trim and Balance Lecture from Singles On Sailboats Spring Training.

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  • Sail Trim And Balance Fundamental

    1. 1. Fundamental Sail Trim and Balance with Kristen “kb” Berry
    2. 2. Sail Trim and Balance • The Big Question • One Language • Two Modes • Three Sources of Power • Controls • Balance • Putting it all together
    3. 3. What makes a boat go?
    4. 4. Let’s Develop a Common Sail Language
    5. 5. One Language • Most sails have three edges • Most sails have three corners
    6. 6. One Language
    7. 7. One Language Luff
    8. 8. One Language Leech Luff
    9. 9. One Language Leech Luff Foot
    10. 10. One Language Head Leech Luff Foot
    11. 11. One Language Head Leech Luff Foot Tack
    12. 12. One Language Head Leech Luff Clew Foot Tack
    13. 13. One Language LUFF Chord Draft Camber Leech
    14. 14. What are the Two Modes of Sailing? • Fast and Slow? • Cruising and Racing? • Upwind and Downwind?
    16. 16. Push Mode
    17. 17. Push Mode • Sail acts as a WIND block to the wind. • More wind = more power H H • More area = LL more power
    18. 18. Pull Mode
    19. 19. Pull Mode • Attached air WIND flows over both sides from leading to trailing edge • Outside air flows faster because of L H camber H L • Creates heel & forward force
    20. 20. Pull Mode - Keel Lift Keel Lift • Keel lift works the same way, below the water. L • Water flows over the curved surface of the keel. Leeway • Because of leeway, high H pressure builds on the LEEWARD side and keel lift occurs.
    21. 21. Pull Mode - The Watermelon Seed • When Sail Lift and Keel Combined Lift balance, the boat Force moves forward Keel Lift • Keels takes us upwind and sails take us downwind • We must have flow and Sail Lift balance
    22. 22. Pull mode is really FLOW mode.
    23. 23. So what mode are you sailing in?
    24. 24. CLOSE HAULED
    25. 25. Beam Reaching
    26. 26. Broad Reaching
    27. 27. WIND Close Hauled No Go ZONE Beam Reach Broad Reach Run
    28. 28. What are the three sources sail power?
    29. 29. Angle of Attack The angle of a sail’s CHORD to the apparent wind.
    30. 30. WIND WIND WIND 0 45 60 Luffing Proper AoA Stalled
    31. 31. So what do telltales show us about AoA?
    32. 32. Attached Airflow Luff
    33. 33. Attached Airflow Leech
    34. 34. When in doubt... Let it out, until it luffs. Often doubt... Rarely in error.
    35. 35. Draft The AMOUNT of camber in a sail and the LOCATION of the deepest point of camber.
    36. 36. Flat Deep Shape Shape Horizontal Profile: A deeper sail is more powerful but will also generate more drag. A flat sail has less drag, but generates less power in lighter winds. Deeper sails for light air and flatter sails for heavier air.
    37. 37. Flat Mainsail Shape
    38. 38. Deep Mainsail Shape
    39. 39. Deep sails for light air. Flat sails for heavy air.
    40. 40. Twist The difference in Angle of Attack from head to foot of a sail. The amount of leeward falloff of a sail’s leech.
    41. 41. UPWIND TWIST Note the top batten relative to the boom. Both are showing the CHORD of the mainsail. The top batten is pointing to leeward while the boom is pointing behind the boat.
    42. 42. DOWNWIND TWIST Twisting OPEN the leech allows the wind to flow freely from leading edge to trailing edge. More twist equals more flow.
    43. 43. TWIST Wind Speed
    44. 44. Sail Controls • Primary Mainsail Controls • Primary Jib/ Genoa Controls
    45. 45. Main Controls Angle of Attack Draft Twist Angle of Chord to Wind Amount and Location Difference in AoA Halyard ✔ Sheet ✔ ✔ Traveler ✔ Vang ✔ ✔ Outhaul ✔ Backstay ✔ ✔ Cunningham ✔
    46. 46. Jib/Genoa Control Angle of Attack Draft Twist Angle of Chord to Wind Amount and Location Difference in AoA Halyard ✔ Sheet ✔ ✔ ✔ Lead Car Blocks ✔ ✔ ✔ Backstay ✔
    47. 47. BALANCE • How does sail trim affect affect balance? • How does heel affect balance?
    48. 48. Mainsail Center of Headsail Effort Center of Effort ☢ ✇☢ Combined Center of Effort Center of ✇ Lateral Resistence
    49. 49. Boat Sails Boat Turns Straight To Port View from astern Boat is heeled Boat is level to starboard
    50. 50. ☢ ☢ View from astern ✇ ✇ Boat is level Boat is heeled And TURNING and steering straight
    51. 51. What do we want? When do we want it? and how do we get it?
    52. 52. Light Air Days • GIVE ME POWER! • MORE FLOW! • MORE DRAFT! • MORE TWIST!
    53. 53. Light Air Days No Stall! Eased sheets, boom off AoA centerline. All telltales streaming aft. Not steering close hauled. Ease halyard, outhaul, backstay, Draft cunningham. Move jib lead forward. Open twist to promote flow at top Twist of sail. Jib and main should “match” Leeward heel to promote sail camber. Forward weight to reduce Balance drag. Trim crew weight to helm “feel.” Slight tug.
    54. 54. Moderate Air Days • No compromises • Max point and speed • Minimum Twist • Design Draft • Design Heel - Flatter is faster
    55. 55. Moderate Air Days Max trim, slight stall for point. Boom on centerline. Inside jib AoA telltale lifting, top leech telltale slight stall. Draft Moderate depth, starting to flatten Twist No twist for maximum power. Designed heel. Less than 10 Balance degrees. Trim crew weight to helm “feel.” Neutral tug.
    56. 56. Heavy Air • WHOA!!!!!! • Depower sails • Open AoA for waves • Keep the boat balanced
    57. 57. Heavy Air Days Traveler down for open AoA. Jib/ AoA Genoa eased or even moved outboard Flat, Flat, Flat. Tight halyards and Draft OBC’s Twist Lots of twist to help depower. Reduce heel by moving crew weight Balance to windward. Balance CEs to keep helm pressure to light tug.
    58. 58. Thank you! • Let’s go sailing! • Submit your question cards. • Stay in touch - my pledge to you. • Resources.